onTraceEvent

The marshalled ParcelableTraceEvent trace event. See ParcelableTraceEvent for how non-parcelable trace event arguments are handled. This is a MarshalledTraceEvent to ensure the service implementation doesn't need to unmarshal the trace event to forward trace events from one service to another. Unmarshalling the trace event is undesired because it requires all trace event argument types to be present on the classpath of the service as well.